I had just a 12 and didn't sound right. I added a pioneer 10 to it and so much better. First time I've mixed different size speakers. Got my 12 for lows and 10 for the highs. My trunk is just so small. I couldn't even get my Vega 15 in it. My car is a 96 tho. My buddy has a 06 and 3 times the trunk space. Get you one of those Jl audio 10.5, I know they're expenive but sound good. IMO those are the only single subs that will sound right and complete. If you go duals Rockford has always put a smile on my face.